This disclosure relates to a surface treatment for ear tips including noise-blocking earplugs and ear interfaces for audio headphones or hearing aids.
Earplugs for blocking sound are available in a variety of materials and shapes, and are generally designed to fit inside some part of the ear canal and/or outer ear. Many types of audio headphones and most hearing aids also include parts called “ear interfaces” designed to fit inside some part of the ear canal and/or outer ear. Ear interfaces may serve to hold the device in place, to control acoustic coupling between acoustic elements and the wearer's ear drum, and to block outside sound from entering the ear. Headphone ear interfaces may be custom-molded to a particular wearer's ear or may have a universal fit designed to fit some portion of the general population. Hearing aid ear interfaces are almost always custom-molded. Noise-blocking earplugs may also be custom molded, especially for workers who spend significant time in high-noise environments, such as factory workers or soldiers. We use ear tips generically to refer to both noise-blocking earplugs and audio headphone or hearing aid ear interfaces.
As shown in FIG. 1, an earplug 30 maintains contact with the skin of the ear 10 in order to remain in place and to block sound from passing through any gaps between the earplug and the skin. In particular, earplugs designed to block sound need to have intimate contact with the ear skin, which is commonly achieved through the use of soft materials such as silicone that conform to the shape of the ear.
FIG. 1 also identifies several parts of human ear anatomy referred to below. The ear canal 12 is the passageway from the eardrum 14 through the head 16 to the outer environment. The pinna 18 refers to the structures of the ear located outside of the head. The pinna includes several structures, including the helix 20, antihelix 22, tragus 24, and antitragus 26. In the figure of FIG. 1, the tragus 24 and part of the helix 20 would be forward of the plane where the section of the head 16 was taken, as shown by the dotted lines. The concha 28 is the bowl-shaped space around the outer end of the ear canal, and is bounded by the tragus, antitragus, and antihelix.